Add "wire" example

Author: mgeier

doc/examples.rst

@@ -1,11 +1,18 @@
 :orphan:
 
-Example Program(s)
-==================
+Example Programs
+================
 
 Play a Sound File
 -----------------
 
 :download:`play_file.py <../examples/play_file.py>`
 
 .. literalinclude:: ../examples/play_file.py
+
+Input to Output Pass-Through
+----------------------------
+
+:download:`wire.py <../examples/wire.py>`
+
+.. literalinclude:: ../examples/wire.py

examples/wire.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+"""Pass input directly to output.
+
+See https://www.assembla.com/spaces/portaudio/subversion/source/HEAD/portaudio/trunk/test/patest_wire.c
+
+"""
+import argparse
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("-i", "--input-device", type=int, help="input device ID")
+parser.add_argument("-o", "--output-device", type=int, help="output device ID")
+parser.add_argument("-c", "--channels", type=int, default=2,
+                    help="number of channels")
+parser.add_argument("-t", "--dtype", help="audio data type")
+parser.add_argument("-s", "--samplerate", type=float, help="sampling rate")
+parser.add_argument("-b", "--blocksize", type=int, help="block size")
+parser.add_argument("-l", "--latency", type=float, help="latency in seconds")
+args = parser.parse_args()
+
+try:
+    import sounddevice as sd
+
+    callback_status = sd.CallbackFlags()
+
+    def callback(indata, outdata, frames, time, status):
+        global callback_status
+        callback_status |= status
+        outdata[:] = indata
+
+    with sd.Stream(device=(args.input_device, args.output_device),
+                   samplerate=args.samplerate, blocksize=args.blocksize,
+                   dtype=args.dtype, latency=args.latency,
+                   channels=args.channels, callback=callback):
+        print("#" * 80)
+        print("press Return to quit")
+        print("#" * 80)
+        input()
+
+    if callback_status:
+        print(callback_status)
+except BaseException as e:
+    # This avoids printing the traceback, especially if Ctrl-C is used.
+    raise SystemExit(str(e))